1. Field of the Invention
The present invention relates to a calibration method for detectors and to power measurement instruments using a detector calibrated according to the calibration method. Detectors are, for example, cameras with a photodetector part comprising a plurality of photodetector devices.
2. Description of the Prior Art
Conventionally, DNA chips have been used for identification and fractionation (for example, detection of DNAs or detection of whether gene DNAs exist or not) of, for example, biopolymers.
In DNA chips, fragments of known DNAs, for example, in thousands of or tens of thousands of types are fixed in each of the sites on a substrate. When fragments of unknown DNAs are run onto these DNA chips, DNAs of the same type are hybridized and combined. After unknown DNAs that have not been combined are removed through rinsing, excitation light (laser light) is irradiated to the remaining DNAs. Unknown DNAs are labeled with fluorescent substances beforehand. Excited fluorescent substances irradiated by excitation light generate fluorescence. As a result, light and dark areas appear in each site corresponding to whether hybridization has occurred or not.
This observation of light and dark areas is performed with such equipment as fluorescent scanning instruments using confocal laser optical systems as, for example, described in “DNA Analyses and Optical Technologies” by Toru Makino and Kyoichi Kano in “Optical Technologies in Life Science” of the “KOGAKU (Japanese Journal of Optics)” magazine, Volume 28 No. 10 (1999), pages 549 to 552, published in 1999 by the Optical Society of Japan, a division of the Japan Society of Applied Physics. For example, photomultipliers that enable highly sensitive detection are used for detectors in fluorescence observation.
Although power meters are used for detectors in some cases, power meters can only perform detection in zero dimensions in a spaceand, therefore, cannot measure precisely samples with shapes such as biochips including DNA chips or plasma displays.
Because these samples has intensity patterns caused by their shapes.
In the meantime, these conventional detectors such as fluorescent scanning instruments have the following problems because they cannot measure absolute power:
(1) It is not possible to compare values of detectors' output signals among instruments.
(2) Since the amount of gene expression is not known in biochip measurements, the only method is to mix, for example, known genes and perform comparative measurements, thereby causing such instruments to become expensive.